From 3e56a78b50e4794f89295278d477ad605c22471b Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Sun, 22 Apr 2012 13:37:24 +0200
Subject: [PATCH] nspawn: add -b switch to automatically look for an init
binary (cherry picked from commit
0f0dbc46ccf5aaaf3131446d0a4d78bc97a37295)
Conflicts:
TODO
---
man/systemd-nspawn.xml | 10 ++++++++++
src/nspawn/nspawn.c | 29 +++++++++++++++++++++++++++--
src/shared/util.h | 2 ++
3 files changed, 39 insertions(+), 2 deletions(-)
diff --git a/man/systemd-nspawn.xml b/man/systemd-nspawn.xml
index 47aa4a7..31baa01 100644
--- a/man/systemd-nspawn.xml
+++ b/man/systemd-nspawn.xml
@@ -142,6 +142,16 @@
</varlistentry>
<varlistentry>
+ <term><option>--boot</option></term>
+ <term><option>-b</option></term>
+
+ <listitem><para>Automatically search
+ for an init binary and invoke it
+ instead of a shell or a user supplied
+ program.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
<term><option>--user=</option></term>
<term><option>-u</option></term>
diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
index 0d0d987..c1b1dc7 100644
--- a/src/nspawn/nspawn.c
+++ b/src/nspawn/nspawn.c
@@ -56,6 +56,7 @@ static char *arg_directory = NULL;
static char *arg_user = NULL;
static char **arg_controllers = NULL;
static bool arg_private_network = false;
+static bool arg_boot = false;
static int help(void) {
@@ -63,6 +64,7 @@ static int help(void) {
"Spawn a minimal namespace container for debugging, testing and building.\n\n"
" -h --help Show this help\n"
" -D --directory=NAME Root directory for the container\n"
+ " -b --boot Boot up full system (i.e. invoke init)\n"
" -u --user=USER Run the command under specified user or uid\n"
" -C --controllers=LIST Put the container in specified comma-separated cgroup hierarchies\n"
" --private-network Disable network in container\n",
@@ -83,6 +85,7 @@ static int parse_argv(int argc, char *argv[]) {
{ "user", required_argument, NULL, 'u' },
{ "controllers", required_argument, NULL, 'C' },
{ "private-network", no_argument, NULL, ARG_PRIVATE_NETWORK },
+ { "boot", no_argument, NULL, 'b' },
{ NULL, 0, NULL, 0 }
};
@@ -91,7 +94,7 @@ static int parse_argv(int argc, char *argv[]) {
assert(argc >= 0);
assert(argv);
- while ((c = getopt_long(argc, argv, "+hD:u:C:", options, NULL)) >= 0) {
+ while ((c = getopt_long(argc, argv, "+hD:u:C:b", options, NULL)) >= 0) {
switch (c) {
@@ -133,6 +136,10 @@ static int parse_argv(int argc, char *argv[]) {
arg_private_network = true;
break;
+ case 'b':
+ arg_boot = true;
+ break;
+
case '?':
return -EINVAL;
@@ -1024,7 +1031,25 @@ int main(int argc, char *argv[]) {
setup_hostname();
- if (argc > optind)
+ if (arg_boot) {
+ char **a;
+ size_t l;
+
+ /* Automatically search for the init system */
+
+ l = 1 + argc - optind;
+ a = newa(char*, l + 1);
+ memcpy(a + 1, argv + optind, l * sizeof(char*));
+
+ a[0] = (char*) "/usr/lib/systemd/systemd";
+ execve(a[0], a, (char**) envp);
+
+ a[0] = (char*) "/lib/systemd/systemd";
+ execve(a[0], a, (char**) envp);
+
+ a[0] = (char*) "/sbin/init";
+ execve(a[0], a, (char**) envp);
+ } else if (argc > optind)
execvpe(argv[optind], argv + optind, (char**) envp);
else {
chdir(home ? home : "/root");
diff --git a/src/shared/util.h b/src/shared/util.h
index 42d1f0c..f4190a3 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -100,6 +100,8 @@ bool streq_ptr(const char *a, const char *b);
#define new0(t, n) ((t*) calloc((n), sizeof(t)))
+#define newa(t, n) ((t*) alloca(sizeof(t)*(n)))
+
#define newdup(t, p, n) ((t*) memdup(p, sizeof(t)*(n))
#define malloc0(n) (calloc((n), 1))